As a system for realizing an increase in the speed of mobile radio communication, in recent years, study and standardization activity of a fourth generation mobile communication system have been promoted. In an IMT-Advanced which is one of fourth generation cellular communication systems, a maximum transmission speed is set to 100 Mbps in a high speed moving environment, and 1 Gbps in a low speed moving environment or a fixed environment. A frequency band used in the IMT-Advanced includes the 3.5 GHz band by which a bandwidth of 100 MHz is available in uplink and downlink. In the 3.5 GHz band, frequencies are higher than those in the 800 MHz band and 2 GHz band which are mainly used in a related art radio communication system, resulting in a risk that a transmission distance of electric waves is shortened. This leads to such a problem that an area in which a sufficient reception intensity is not obtained by the conventional number of base stations is broadened and the transmission speed set in the IMT-Advanced cannot be achieved. As a solution to the problem, the number of base stations is increased. A new base station is provided in the area where the sufficient reception intensity is not obtained by the conventional number of base stations to enable radio communication to be conducted. Also, another effective countermeasure is to increase the reception intensity through a radio communication device such as a relay station that relays a communication between the base station and the mobile station.
In the system of this type, the number of radio communication devices such as the base stations or the relay stations per unit area is increased, and a case in which plural radio communication devices that can be connected to the mobile station exists is liable to occur as compared with the conventional art.
When the plural radio communication devices that can be connected to the mobile station exists, there is a need to select an access point from the plural radio communication devices. As a criterion for selecting the radio communication device to be connected, there is a method of conducting selection based on a radio quality between the base station and the mobile station as disclosed in Patent Literature 1. Also, as an example of a protocol stack used in the radio communication system, Non Patent Literature 1 is standardized.